Where do I edit "Create a Site" text?

Where do I go to edit the text in "Create a Site" in Pro Sites?

Specifically, this text:

By filling out the form below, you can add a site to your account. There is no limit to the number of sites that you can have, so create to your heart's content, but blog responsibly!

If you’re not going to use a great domain, leave it for a new user. Now have at it!

I can't find it anywhere. Thanks!